Reaction products of alkanol amines with bicyclic amide acetals and their application in polyurethane polymers

ABSTRACT

The process for preparing a polyurethane by reaction of a polyol component and a polyisocyanate, the improvement comprising using as part of the polyol component a polyol produced by reaction of a bicyclic amide acetal and an alkanol amine at a temperature of at least 120° C.

This is a continuation of U.S. patent application Ser. No. 740,663,filed June 3, 1985, now U.S. Pat. No. 4,600,796.

This invention relates to a process for reacting bicyclic amide acetalswith alkanols amines such as diethanol amine at temperatures in therange of 120°-240° C. to yield new amido-amine-ether containing polyolsand to use of these new polyols in polyurethane polymers.

The reaction of bicyclic amide acetals with high boiling secondaryamines has been described in Synth., 16, 1971 as an unpublished result.No previous description of the reaction of amide acetals with hydroxylgroup containing materials has been described. No reaction of alkanolamines with bicyclic amide acetals has been previously described.Bicyclic amide acetals which are useful in this invention include thosedescribed in Copending U.S. patent application Ser. Nos. 641,238 nowU.S. Pat. No. 4,605,746, and 641,242, now abandoned filed 8/16/84.

I have discovered that alkanol amines will react with bicyclic amideacetals at temperatures of about 120° C. and above and preferably at atemperature in the range of from about 120° C. to about 240° C. to yieldpolyols containing amido-amine-ether groups.

The bicyclic amide acetals useful in this invention are those conformingto the following Formulas I, II and III: ##STR1## wherein R representshydrogen, an alkyl group having from 1 to 20 carbon atoms, an aryl grouphaving from 6 to 12 carbon atoms or an alkaryl group having from 7 to 20carbon atoms, R' represents hydrogen, an alkyl group having from 1 to 10carbon atoms, an aryl group having from 6 to 12 carbon atoms, an alkarylgroup having from 7 to 15 carbon atoms or an ether group having from 1to 20 carbon atoms, and R" represents an alkylene group having from 1 to20 carbon atoms or an alkylene ether group having from 1 to 20 carbonatoms.

The alkanol amines which are useful in this invention are thoseincluding diethanol amine having the formulas IV and V ##STR2## where R'has the foregoing definition and A and B independently represent analkylene group having at least 4 carbon atoms and no more than about 20carbon atoms carbon or an alkylene ether group containing at least 3 andas many as 100 or more carbon atoms, and n is a number of from 1 to 3.

In the process of this invention the amine group as well as the hydroxylgroups of the alkanol amine react with the bicyclic amide acetal to givethe ring opening products providing new polyols having amide, amine andether groups in the backbone. This reaction is illustrated in itssimplest form in the following reaction: ##STR3##

In the process of this invention the major part of the reaction proceedsvia the ring opening of the bicyclic amide acetal to form amido-ethergroups in the chain and hydroxyl terminal group and a minor part of thereaction (about (10%) produces product having tertiary amine-ether-estergroups. This is believed to be the case based on the infrared spectrumof the reaction mixtures which show the presence of strong tertiaryamide band at 1620-40 reciprocal centimeters (cm⁻¹) and hydroxyl band atabout 3350-3450 cm⁻¹ and a weak band at about 1730 cm⁻¹ due tocarboxylate groups.

I have found that in the 1:1 molar reaction between bicyclic amideacetal and diethanol amine at about 160 degrees C. some diethanol amineremains unreacted while all of the bicyclic amide acetal is consumed inthe reaction. Similarly when an excess of the bicyclic amide acetal (2moles per mole of ethanol amine) is used in the reaction all of thebicyclic amide acetal is consumed and products having higher molecularweight and low hydroxyl number are obtained. This clearly demonstratesthat in the reactions of alkanol amines with bicyclic amide acetal boththe amino groups and the hydroxyl groups undergo reaction.

The process of this invention can be carried out in the presence of acatalyst such as an alkali or alkaline earth metal or their salts infrom 0.01 to 5 mole % based on the alkanol amine.

The polyols obtained in the process of this invention can be used in theproduction of polyurethane polymers. Polyurethanes produced from thepolyols of this invention can be used in reaction injection molding(RIM) processes, thermoset plastic synthesis, adhesive formulations,rigid and semi-rigid foam formation and in other applications some ofwhich are demonstrated in the following Examples. Because the polyols ofthis invention also contain tertiary amine groups, they can be used asreactive catalysts in the polyurethane/isocyanurate synthesis.Furthermore, the polyols of this invention have been found to bereactive compatibilizers for the fluorinated hydrocarbon blowingagent-polyols mixtures used in rigid polyurethane foam production.

The polyisocyanates useful in the preparation of polyurethanes byreaction with the polyols of this invention include organic isocyanateshaving at least two isocyanate groups per molecule. The polyisocyanatescan be of low, high or intermediate molecular weight and can be any of awide variety of organic polyisocyanates including ethylene diisocyanate,trimethylene diisocyanate, dodecamethylene diisocyanate, hexamethylenediisocyanate, hexamethylene diisocyanate trimer, tetraethylenediisocyanate, pentamethylene diisocyanate, propylene-1,2-diisocyanate,2,3-dimethyl tetramethylene diisocyanate, butylene-1,2-diisocyanate,butylene-1,3-diisocyanate, 1,4-diisocyanato cyclohexane,cyclopentene-1,3-diisocyanate, p-phenylene diisocyanate, 1-methylphenylene-2,4-diisocyanate, naphthalene-1,4-diisocyanate, toluenediisocyanate, diphenyl-4,4'diisocyanate, benzene-1,2,4-triisocyanate,xylene-1,4-diphenylene methane diisocyanate, 4,4'diphenylene propanediisocyanate, 1,2,3,4-tetraisocyanato butane,butane-1,2,3-triisocyanate, polymethylene polyphenyl isocyanate, andother polyisocyanates having an isocyanate functionality of at least twowhich are more fully disclosed in U.S. Pat. Nos. 3,350,362 and3,382,215. Polyisocyanates which are polymeric in nature includingisocyanate prepolymers of all types are included in this invention.

The process and products of this invention are further illustrated inthe following illustrative examples.

EXAMPLE 1

Diethanol amine (50 g) and 65 g of a bicyclic amide acetal of Formula Iin which R is methyl and R' is hydrogen were mixed and heated at about160 degrees C. under a nitrogen atmosphere with continuous stirring for3 hours. The solution was subjected to GLC analysis which revealed thecomplete disappearance of the bicyclic amide acetal; however,approximately 20% of the starting diethanol amine still remainedunreacted. The infrared spectrum showed the presence of strong bands dueto amide groups (1620-35 cm⁻¹) and hydroxyl groups (3350-3450 cm⁻¹) anda very weak band due to carboxylate groups (1730 cm⁻¹). Additionalbicyclic amide acetal (39.5 g) was added and the reaction mixture wasfurther heated for 3 hours at 160° C. The GLC analysis indicated thecomplete disappearance of amide acetal and the starting diethanol aminelevel was dropped to about 7%. The hydroxyl number of the mixture ofpolyols was found to be 516.

EXAMPLE 2

The procedure of Example 1 was followed using 59.7 g of the amide acetaland 20 g of diethanol amine. The reaction mixture was heated at 160° C.for 7 hours. The GLC analysis of the solution indicated the completedisappearance of bicyclic amide acetal and greater than 98% conversionof diethanol amine. The infrared spectrum showed strong bands due toamide and hydroxyl groups at about 1620-40 cm⁻¹ and 3350-3450 cm⁻¹respectively. Only trace amounts of ester group band was observed atabout 1735 cm⁻¹. The hydroxyl number of the polyol product was 428.

EXAMPLE 3

This Example and those that follow demonstrate the applications ofpolyols obtained in Examples 1 and 2 in polyurethane polymer synthesisand possible use in adhesives, rigid foams, and the like. A solution of38.4 g of tripropylene glycol and 7.2 g of polyol mixture described inExample 1 was prepared. A 14 g portion of this polyol was mixed with37.2 g of polyterephthalic ester polyol blended with diethylene glycolas described in U.S. Pat. No. 3,647,759 having a hydroxy number of 350(commercially available as Chardol 570 from Chardonol Corp.) and thesolution was degassed and mixed with 456.6 g of degassed liquid4,4'-methylene bis (phenyl isocyanate) having an isocyanate equivalentweight of about 144. The resulting mixture was poured into a moldprepared by spacing two silicone release coated glass plates apart inparallel fashion by 1/8 inch thick spacers. Polymerization occurred atambient temperature within two minutes to give a solid polymer. Themolded polymer was postcured in the mold for an additional hour at 135°C. The resulting cured polyurethane was found to have a notched izodimpact strength (ASTM D256) of 0.6 foot pounds/inch of notch, unnotchedizod impact strength of greater than 14.4 foot pounds/inch, heatdistortion temperature (ASTM D648-56) of 85° C., tensile yield strength(ASTM D790) of 17,875 psi and flexural modulus (ASTM D648) of 403,069psi.

EXAMPLE 4

The procedure of Example 3 was followed using 40 g of tripropyleneglycol, 10 g of the polyol mixture of Example 1 and 81 g of thepolyisocyanate. The cured polyurethane was found to have an izod impactstrength of 0.7 foot pounds/inch of notch, heat distortion temperatureof 84° C., tensile yield strength of 17,883 psi and flexural modulus of408,207 psi.

EXAMPLE 5

The procedure of Example 3 was followed using 40 g of tripropyleneglycol, 10 g of the polyol of Example 2 and 82 g of the polyisocyanate.The cured polymer was found to have an izod impact strength of 0.4 footpounds/inch of notch, flexural strength of 12,554 psi and flexuralmodulus of 271,375 psi.

EXAMPLE 6

This experiment demonstrates that the polyols obtained from thereactions of diethanol amine with bicyclic amide acetals can be used inadhesive formulations. A mixture of 9 g of tripropylene glycol and 2.5 gof the polyol of Example 2 was degassed and mixed with 128 g of thepolyisocyanate of Example 3. The resulting viscous liquid was appliedbetween two one-inch wide and four-inch long sheet molding compound(SMC) panels with a one square inch overlap for the adhesive bond. Thebond thickness was 30 mils which was achieved by placing some 30 milsdiameter glass beads between the panels before applying the adhesive.The adhesive resin was then cured by allowing it to stand for an hour atroom temperature followed by a post curing treatment at 120° C. for 30minutes. Testing of the resulting adhesive bond showed that failure ofthe SMC substrate occurred first at about 400 psi. Similarly theadhesive bond was prepared and tested on cold rolled steel sheets andthe resulting cured bond was found to have a shear strength of about1850 psi.

EXAMPLE 7

This experiment demonstrates the use of the polyols of this invention asreactive compatibilizing agents for fluorocarbon-poly (terephthalicester) polyol mixtures and their use in rigid foam applications. To 11.0g of poly (terephthalic ester) polyol (hydroxy number 350, Chardol 570from Chardonol Corp., more fully described in U.S. Pat. No. 3,647,759)was added 2.2 g of the polyol of Example 2 and to the resulting solutionwas added 5.0 g of fluorocarbon blowing agent (Freon F11B, DuPont). Themixture was vigorously stirred to give a homogeneous solution and thehomogeneous solution did not break when kept at room temperatureundisturbed for 15 minutes.

EXAMPLE 8

This Example is for comparison purposes and is outside the scope of thisinvention. The procedure of Example 7 was followed using 10.1 g of poly(terephthalic ester) polyol and 4.1 g of Freon F11B. The homogeneoussolution upon standing undisturbed at room temperature showed phaseseparation in less than 15 minutes.

EXAMPLE 9

A mixture of 13.4 g of poly (terephthalic ester) polyol blended withdiethylene glycol with hydroxy number 447 (commercially available asChardol 560 from Chardonol Corp.), 2.2 g of polyol of Example 1, 0.3 gof tertiary amine catalyst, N,N',N"-tris(dimethylaminopropylhexahydrotriazine), 0.4 g of silicone surfactant (DC 193 from DowCorning) and 6.8 g of Freon F11B was mixed with 22 g of thepolyisocyanate of Example 3 in a paper cup. A vigorous reaction occurredto give a rigid foam. The foaming characteristics were: a cream time of18 seconds, a rise time of 28 seconds and a tack free time of 34seconds. The resulting foam was post cured at 100° C. for five minutesto give a non-friable foam having a 1.6 pounds/cubic foot density and acompressive strength of about 18 psi (rise direction) and 15 psi (widthdirection).

EXAMPLE 10

The procedure of Example 9 was followed using 13.5 g of poly(terephthalic ester) polyol, 2.3 g of polyol of Example 2, 0.3 g oftertiary amine catalyst, 0.4 g of silicone surfactant, 10 g of talcfiller, 6.4 g of Freon F11B and 22 g of polyisocyanate. The foamingcharacteristics were: cream time of 18 seconds, rise time of 30 seconds,and tack free time of 37 seconds. The resulting rigid foam was postcured at 100° C. for 5 minutes and then was found to have a compressivestrength of 19.5 psi (rise direction) and 15 psi (width direction). Thisfoam had improved fire retardancy (self-extinguishing) when compared tothe foam of Example 9.

EXAMPLE 11

To 52.5 g of diethanol amine was added 0.23 g of sodium and the mixturewas heated at 50° C. for 15 minutes during which time all of the sodiumreacted to give a clear solution. This solution was mixed with 129 g ofthe bicyclic amide acetal described in Example 1 and the resultingmixture was heated at about 160° C. for 51/2 hours. GLC of the resultingreaction mixture showed a complete consumption of the diethanol amine.The final viscous liquid polyol product was found to have a hydroxylnumber of 530 and the infrared spectrum showed the presence of amidegroups (1630 cm⁻¹) and hydroxyl groups (3350-3450 cm⁻¹).

EXAMPLE 12

The procedure of Example 3 was followed using 5 g of the polyol ofExample 11, 20 g of tripropylene glycol and 36.25 g of liquid4,4'-methylene-bis(phenyl isocyanate). The polymer sheet obtained aftercuring at 100° C. for 1 hour followed by 1 hour at 130° C. had a notchedizod impact strength of 0.8 foot pounds/inch of notch.

EXAMPLE 13

The procedure of Example 3 was followed using 2.5 g of the polyol ofExample 11, 10 g of tripropylene glycol, 25 g of polyterephthalic esterpolyol and 47 g of liquid 4,4'-methylene-bis(phenyl isocyanate). Thecured polymer sheet was found to have a notched izod impact strength of0.8 foot pounds/inch of notch.

I claim:
 1. In the process for preparing a polyurethane by reaction of apolyol component and a polyisocyanate, the improvement comprising usingas part of the polyol component a polyol produced by reaction of abicyclic amide acetal and an alkanol amine at a temperature of at least120° C.
 2. The process of claim 1 wherein the bicyclic amide acetal isone conforming to at least one of the Formulas I, II or III ##STR4##Wherein R represents hydrogen, an alkyl group having from 1 to 20 carbonatoms, an aryl group having from 6 to 12 carbon atoms or an alkarylgroup having from 7 to 20 carbon atoms, R' represents hydrogen, an alkylgroup having from 1 to 10 carbon atoms, an aryl group having from 6 to12 carbon atoms, an alkaryl group having from 7 to 15 carbon atoms, analkaryl group having from 7 to 15 carbon atoms, or an ether group havingfrom 1 to 20 carbon atoms, and R" represents an alkylene group havingfrom 1 to 20 carbon atoms or an alkylene ether group having from 1 to 20carbon atoms.
 3. The process of claim 2 wherein the alkanol amine is atleast one having formula IV or V ##STR5## wherein R' has the foregoingdesignation, A and B independently represent an alkylene group having atleast 4 carbon atoms or an alkylene ether group containing 3 or morecarbon atoms and n is a number of from 1 to
 3. 4. The process of claim 3wherein the bicyclic amide acetal is one of formula I wherein R ismethyl and R' is hydrogen and the alkanol amine is diethanol amine.